第1个回答 2022-06-13
16*75 - 315/21
=16*5*15-5*63/21
=16*5*(3*5) - 5*(3*21)/21
=16*5*(3*5) - 5*3
=(3*5)*(16*5-1)
=3*5*79
=3*5*(80-1)
=3*(5*80)-3*5
=3*400-15
=1200-15
=1185
或者:
16*75 - 315/21
=16*75-15
=16*15*5-15
=15*(16*5-1)
=15*79
=(3*5)*(80-1)
=3*400-15
=1185